JPH02140172A - Capillary dialysis apparatus - Google Patents

Abstract

PURPOSE: To enable to insert different numbers of capillaries corresponding to a step of the volume, by giving twisted thread in parallel to the capillary extending direction, almost uniformly distributing twisted thread across the section of a bundle, and elastically filling the section of a dialyzing room with bundles of capillaries. CONSTITUTION: Blood enters a flow-in room 8 through a connection tube 7, is distributed into capillaries 2 and flows through it. Blood from individual capillaries 2 is collected in a flow-out room 9 and flows out through a connection tube 7. Dialyzate flows in the arrow mark 13 direction through two tubes 11, 12 and blood moves in the arrow mark 14 direction. A twist 15 consisting of fabric thread is arranged between capillaries 2 so as to almost uniformly distributed across the section of an inside room. The twist 15 is not directly contacts with the capillaries 2 but loosely extended to the capillary 2 direction. A twist 15 has the diameter almost matching the outer diameter of an individual capillary 2. Since the mixing rate of twist 15 against the number of capillaries 2 can be freely selected, the volume in different steps is enabled using the size of a single housing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a generally tubular housing and a bundle of capillary tubes attached at opposite ends within the housing and connected to blood inflow and outflow chambers sealed from each other and from the housing by an implant. The present invention relates to a capillary dialysis device in which dialysate in a dialysis room flows around capillary tubes in which fabric-like twisted threads are arranged. Such capillary dialysis devices are mainly used in hemodialysis devices.

The capillary tubes vary in diameter due to their manufacture, thus resulting in different bundle diameters when the capillary tubes are bundled and inserted into the housing. On the other hand, it has sometimes been possible to equip the same housing with different numbers of capillaries to provide dialysis devices with different stages of capacity. Therefore - in the boat the capillary can move laterally in the housing and is pressed integrally to one side, so that in each case the displacement is uneven and does not evenly fill the cross section of the housing. There is some degree of capillary spacing that is greater when within and less when present. This irregularity also causes the flow of dialysate around the capillary to behave differently across the cross section. At this time, there are some parts where the dialysate flows rapidly due to short circuits, and other parts have only a small impact or no shock at all.

According to US Pat. No. 4,293,418, this problem is solved by attaching individual capillaries or several capillaries together and wrapping or looping the thread around them. The twisted yarn may be wound spirally or twisted and overlapped. The twist is intended to be equivalent to a spacer around the individual capillaries. In this case too, the spacer threads are supported in some cases directly against the wall of the capillary, and in other cases against the spacer threads of adjacent capillaries, so that they are not wound. Irregularities occur in the flow of dialysate when the vertical capillaries abut each other.

Furthermore, the spacer twist is effective only at successive intervals;
1. It is not continuously effective over the entire length of the capillary. The manufacture is quite expensive since corresponding mechanical steps have to be carried out. However, a significant disadvantage of spacer threads is that their arrangement prevents the capillaries from expanding when they become wet with dialysate. When using woven yarns, this drawback is eliminated to a considerable extent. However, compatibility with such spacer threads cannot be provided by wrapping around the capillaries in such a way that different numbers of capillaries are housed in an orderly manner within the same housing to provide different levels of capacity.

Methods are already known in which the individual capillaries are stitched together at intervals in phase n so that a final mat-like structure is formed which is then rolled up. The stitching strands are perpendicular to the capillaries and thus also perpendicular to the flow of dialysate and, like known spacer strands, are usually an impediment to the flow of dialysate. The strands may also attract air bubbles that remain within the dialysis machine and increasingly impede further passage.

On the other hand, the basic disadvantage of looped threads, spacer threads, etc. or stitched threads is that the outer diameter of the capillary containing the thread usually increases by this thread, so that fewer capillaries can be accommodated in the housing. It is what happens. The individual treatment of capillaries with spacer threads or stitching threads also normally concerns all capillaries arranged within the housing.

The basic aim of the invention is to make it possible to insert different numbers of capillaries into the same housing depending on the volume level. Nevertheless, the capillaries are usually distributed in an orderly and uniform manner over the cross-section, and the disadvantages of the dialysate described above do not occur.

According to the invention, this means that the strands are applied parallel to the direction of capillary extension without bonding to the individual capillaries in the capillary bundle;
This is also achieved by distributing this number of strands in the capillary bundle almost uniformly over the cross-section of the bundle, such that the cross-section of the dialysis chamber is elastically filled by the capillary bundle with the strands. . The threads are no longer applied to individual capillaries, but to the capillaries and also to the parts of the dialysis chamber that are not filled with capillaries, respectively. Because of this goal, which is fundamentally different compared to the prior art, and because the threads as stuffing or filling strands are not directly bonded to the individual capillaries, the method is different despite using a similar housing. The relative number of strands to the number of capillaries is directly varied and modified to provide a staged capacity dialyzer. The stuffing strands serve to fill unnecessary space within the dialysis chamber and selectively increase local flow resistance. The cross section of the dialysis chamber is thus filled and the individual capillaries are not reinforced or protected. Stuffed yarn certainly has some flow resistance. Due to its shape as a woven thread, the stuffing thread is one through which the dialysate can flow. Since the twisted threads do not provide a sealing effect on the dialysate, the capillary pre-effect is not lost. Due to the elasticity of the threads and their highly uniform distribution in the bundle, a reliable uniform distribution of the capillaries within the dialysis chamber is achieved. This does not result in a desirable flow path with a short-circuiting effect. A short dialysis flow path is created, which is necessary for good dialysis capacity. The elasticity of the stuffed strands also compensates for manufacturing tolerances such as capillary diameter without the need to change the number of capillaries or strands. Such stuffed yarns are of course much easier to manufacture and assemble than conventional spacer yarns looped around individual capillaries. Since the packed yarn can be distributed directly through the capillary bundle, no complicated and cumbersome winding equipment is required. By applying the threads to a bundle of capillaries rather than one or two capillaries, the desired mixing ratio between the capillaries and the threads is obtained, so that dialysis devices of various capacities can be manufactured by this simple method. It is surprising to the person skilled in the art that the previously known bandwidths in the capillary dialysis device capacity step become smaller. The bandwidth of the conduit is shifted towards ideal or optimal capacity. This means that capillary dialysis devices of a given stage volume, manufactured otherwise unchanged, are closer together, ensuring that the volume of a particular stage corresponds more within a narrower range than previously possible. It means. In this regard, safety in use is increased due to smaller volume changes. A similar distribution of the J3G yarns in the capillary bundle also has good effects in the manufacture of dialysis devices. Due to the more uniform and elastic distribution of the bundles within the dialysis chamber, there is a better concentration of the bundles in the centrifugation step when the implant material is inserted.

Waste is also reduced when ultimately a capillary dialysis device with a smaller capacity or fewer capillaries is manufactured. It is precisely this manufacturing method that has hitherto presented special problems.

The present invention provides that a channel not filled with capillaries can be divided into a sufficiently large number of individual small channels so that the resistance to flow, and thus the flow rate, physically depends on the cube of the diameter of the channel. It's based on that.

On the other hand, flow through one pipe with a diameter of 10 mm and a pipe with a diameter of 1 mm.
The relative flow rate of the flow through 100 tubes is the ratio of the cube of the tube diameter to each other, i.e. D3:d3 or 1000:100, 1:10
etc. Therefore, although the flow areas in the two cases are of equal size, only 1710 of the amount that flows through one 100 mm diameter tube flows through the smaller 100 mm channel. The use of flowing through a dialysis device by dividing this single large flow path, for example a short circuit path in a dialysis device according to the prior art, into a corresponding number of smaller flow paths, in particular with the same open flow cross-section, according to the invention. The amount of unused dialysate is reduced by 90%. This results in a significant increase in efficiency. This is also the reason why a step increase in capacity occurs without changing the parameters in terms of equations.

The strands can be approximately the same diameter as the capillary, or they can be slightly smaller in diameter. Thus, twisting yarns with a different degree of size than in the conventional case are used,
In this case, the ratio of the diameter of the looped yarn to the diameter of the capillary tube was approximately 1:10. The aforementioned diameters are the diameters of the strands in their uncompressed state. It should be appreciated that the compression in the bundle is substantially absorbed by the threads since the threads recover more easily than the capillaries.

Depending on the volume level, a bundle of approximately 10 to 25 capillaries is provided with one thread. This mixing ratio is completely arbitrary;
Adapted to the application.

The woven threads are used as strands with a porosity such that the flow resistance to the dialysate matches the flow resistance of the adjacent capillaries. Therefore, instead of blocking the flow with twisted yarn,
Here again, the aim is to cause the dialysate to flow through the circumferential cross-section of the capillary tube. Preferably, a multifilament material is used as the twisted yarn, but a crimped monofilament material may also be used.

The woven, open structure of the threads is important, which on the one hand is compressed, but on the other hand allows the dialysate to flow through it.

The invention will now be further explained with reference to examples.

The capillary dialysis device shown in FIG. 1 has a housing 1 of tubular cross-section in which a number of bundles of capillary tubes 2 are arranged, which in FIG. It is shown. The bundle of capillary tubes 2 is molded at both ends into an embedding 3 which not only mounts the bundle of capillary tubes 2 into the housing 1 but also seals the capillaries from each other and from the wall of the housing 1. The end sides of the embedded material 3 and the capillary tube form a face plate 4. An outer twisted yarn 5 is provided at the end of the tubular housing 1, and a cover 6 is screwed onto this with a gasket (not shown) interposed therebetween.

The cover 6 has a connecting pipe 7 for connecting the pipe lines.

An inlet chamber 8 is thus formed at one end of the housing, and an outlet chamber 9 at the other end. Since the two chambers 8 and 9 are of essentially the same or similar shape, capillaries can be used in one direction or in the other. It will be seen that the blood enters the inflow chamber 8 through the connecting tube 7, where it is distributed into the capillary tube 2 and flows through it. Blood from the individual capillaries 2 is collected in the outflow chamber 9 and flows out through the connecting tube 7.

The internal space 10 between the capillaries 2 between the implants 3 is for the dialysate. The dialysate 1 flows through the two tubes 11 and 12 in the direction of arrow 13, and the blood moves in the direction of arrow 14. Twisted threads 15 of textile-like threads are arranged between the capillary tubes 2 in a roughly -like distribution over the cross-section of the inner chamber 10.

The twisted yarn 15 is not directly joined to the capillary tube 2, but extends loosely in the direction of the capillary tube 2. The twisted yarn 15 has a diameter that approximately corresponds to the outer diameter of the individual capillary tube 2 . It is also possible to use twisted yarns 15 with a slightly smaller diameter. It is important that this thread 15 is made of a woven, elastic material or a multifilament material with other requirements, such as compatibility with dialysate. The strands 15 not only fill the cross section of the inner space 10 when it is not filled with capillary tubes 2, but also support and fix the capillary tubes, thereby avoiding the creation of unnecessary spaces where dialysate traditionally flows as a short circuit. do. Since the dialysate is now distributed more uniformly over the surface of the capillary tube 2, the volume bandwidth in the volume stages is much narrower. This will increase safety during use. The mixing ratio of such threads 15 to the number of capillaries 2 can be chosen freely, so that different levels of capacity are possible using a single housing size. In an example of such use, 250 strands are provided for 6000 capillaries.

FIG. 3 schematically shows a dialyzer according to the prior art in cross section. The capillaries 2 are pressed closely against each other within the housing 1, so that one large flow cross section 16 is open or formed through which a large amount of dialysate flows like a short circuit. , thus resulting in losses to the operation of the dialyzer.

FIG. 4 schematically shows the division of this large flow cross-section into individual flow cross-sections in the form of inserted strands that are more uniformly to non-uniformly distributed over the open surface of the housing 1. There is. As mentioned above, the dependence of the flow resistance and also the flow rate on the cube of the diameter of the flow cross section 16 compared to the many small flow cross sections of the twisted yarn 15 applies here as well.

Let's demonstrate this with a calculation example.

(1) First, consider a dialysis machine in which the ideal division lj of the capillary tube 2 is determined. This dialysis device has 2000 capillary tubes 2 in the housing, and 2000 narrow channels are formed between the capillary tubes 2. The effective diameter of the channel will be 0.3 mm. This results in a flow coefficient of the order of 2000x O,33=54 for this dialyzer with ideal distribution.

(2) In the dialysis machine explained in (1), the 2000 capillaries are not arranged in an ideal distribution across the cross section,
Consider that a larger flow cross-section 16 (FIG. 3) of 5 mm diameter is formed resulting in different flow conditions. There will be an ideal distribution of channel diameters around the flow cross section 16.

It is then reduced to a diameter of 0.278 mm. This results in a flow coefficient of the order of 2000×O,2783=43 for a cross-section of a dialysis machine with ideal distribution.

This corresponds to 36% of the dialysate volume, ie 36% of the dialysate will flow through the cross section of the dialyzer where the capillaries are provided with an ideal distribution.

However, as also assumed, there is a large open flow cross section 16 with a diameter of 5 mm. It can be seen that the flow coefficient of this flow cross section 16 is lX53=75.

This corresponds to 64% of the dialysate volume, i.e. about 2/3
of dialysate flows through the open flow section 16 to no effect. That is, it is transported through the dialysis machine without being used.

(3) Comparatively examine the objectives of the present invention. Here the diameter is 5
A single free section of the flow cross section 16 mm has a diameter of 0.5
It is divided into 100 channels with a diameter of 0.5 m.
This corresponds to inserting 100 twisted yarns 15 of m. Then, the following happens. That is, the flow coefficient 43 of the ideal distributed portion does not change. However, twist 1
The flow rate coefficient of the flow path divided by the insertion of 5 becomes 100X O,53=12.5. This corresponds to a dialysate volume of 22.5%.

The proportion of unused dialysate is thus reduced from 64% to 22.5% by inserting 100 threads, in other words the amount of dialysate is used much better.

This indicates an apparent increase in efficiency.

However, not only is the efficiency increased, but the bandwidth of the capacity stage is reduced by the improvement provided by the present invention. Experiments with two measurements will further demonstrate this.

A) Tests were conducted with a conventional configuration of dialysis device without inserted threads 15. This had 10,000 capillaries. The capillary had an internal diameter of 0.2 mm. The dialysis machine was supplied with a blood flow of 200 ml/min and a dialysis flow of 500 ml/min. 169.1 and urea clearance is ±16.
Forty-eight volume levels were measured. A bundle of 10,000 capillaries was then added with 4% twist 15, otherwise as per the original data. A volume step of 182.5 and a urea clearance of ±7.8 was thus obtained.

The capacity was therefore increased from 169.1 to 182.5, and the displacement to higher capacity was measurably verified. At the same time, the capacity step tolerance decreased from 16.48 to 7.8.

B) The test was carried out on a dialysis machine with 8700 capillaries of internal diameter 0.2 mm, blood flow of 200 m1/min and 500 m
A 1/min dialysis flow was also provided in this case. 178.7
Urea clearance ±4.8 was measured. In comparison, after adding 4% twist to the capillary tube, this dialyzer showed a volume step of the order of 182.3 urea clearance ±1.9.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a capillary dialysis device. FIG. 2 is a cutaway view of a cross section taken along the straight line ``--'''' in FIG. FIG. 3 is a schematic cross-sectional view of a dialysis device according to the prior art. FIG. 4 is a schematic cross-sectional view of a dialysis device according to the invention. (4 others) Procedural amendment 1, Indication of the case, 1999 Patent Application No. 42917 2, Name of the invention Capillary dialysis device 3゜Relationship with the case Patent applicant address Name Zecon GmbH 4. Agent

Claims (1)

Claims: 1. A generally tubular housing and a bundle of capillary tubes sealed from each other and from the housing by an implant attached at both ends within the housing and connecting blood inflow and outflow chambers. In this dialysis device, the dialysate in the dialysis chamber is made to flow around capillaries in which twisted threads made of woven threads are arranged. A twist (1) attached to the bundle of capillaries without bonding to the capillaries of
5) A capillary dialysis device characterized in that the number of capillary tubes having twisted threads is uniformly distributed over the cross section of the dialysis chamber so that the cross section is elastically filled with the bundle of capillary tubes having twisted threads. 2. Capillary according to claim 1, characterized in that the thread (15) is selected to have a diameter equal to and slightly smaller than that of the capillary (2). Dialysis machine. 3. In the bundle of capillaries (2), 10 depending on the capacity level
Capillary dialysis device according to claim 1 or 2, characterized in that one twisted thread (15) is provided for ~25 capillaries (15). 4. The flow resistance of the twisted threads to the dialysate is close to the capillary (
Dialysis device according to claims 1 to 3, characterized in that a woven thread is used as the thread (15) with a porosity that matches the flow resistance of 2). 5. The dialysis device according to claims 1 to 4, characterized in that a multifilament material or a curled monofilament material is used as the twisted yarn (15).